Question

the peppered moth, biston betularia was generally white in color with black speckles. over time a more solid black moth became the more common variety. which of the following best explains the relationship between wing pigmentation and the coloration of a moth’s surroundings? a the frequencies of the different phenotypes in the moth population changed randomly due to genetic drift. b if the surroundings of the peppered moth became darker, those backgrounds conferred a selective advantage to a black variety, as described by natural selection. c there was a gene flow of the black variety, spreading it throughout the moths normal range. d the black variety was a nineteenth century mutation, dominant to the peppered variety. the allele for the peppered trait, being recessive, decreased in frequency over time

Explanation:

• Option A: Genetic drift is random change, but the moth color change is adaptive, not random. Eliminate A.
• Option B: Natural selection occurs when an environment change (darker surroundings) gives a survival/reproductive advantage to black moths (better camouflage), increasing their frequency. This matches the peppered moth example (industrial melanism).
• Option C: Gene flow involves migration, but the problem is about adaptation to surroundings, not migration. Eliminate C.
• Option D: The problem focuses on relationship with surroundings, not allele dominance alone. The key is environmental selection, not just genetic dominance. Eliminate D.

Answer:

B. If the surroundings of the peppered moth became darker, those backgrounds conferred a selective advantage to a black variety, as described by natural selection.